Diffusion mediated selective adsorption of Zn2+ from artificial seawater by MCM-41

• Published in: Microporous and mesoporous materials Vol. 229; pp. 124 - 133
• Main Authors: Mathew, Aneesh, Parambadath, Surendran, Kim, Su Yeon, Ha, Hyung Min, Ha, Chang-Sik
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15.07.2016
• Subjects: Adsorption; Diffusion; MCM-41; Sea water; Zinc; MCM-41; Adsorption; Diffusion; Zinc; Sea water
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2016.04.028

MCM-41 can play a pivotal role as a host material for adsorption applications. In this work, MCM-41 was found to be 100% selective for Zn2+ from artificial seawater containing Ni2+, Li+, Co2+, Cd2+ and Zn2+ as hetero ions. The pristine and Zn2+ ions adsorbed MCM-41 (Zn@MCM-41) were well characterized by various spectroscopic techniques. The selective Zn2+ ion adsorption property of MCM-41 remained intact irrespective of the concentration of Zn2+ ions. The adsorption property of MCM-41 was unaffected by the synthesis strategy of MCM-41. SBA-15 exhibited 85 and 15% mole selectivity for Zn2+ and Cd2+ ions, respectively, under similar experimental conditions. This highlights the unique property of MCM-41 for the selective adsorption of Zn2+ ions from artificial seawater. TEM, FTIR and XPS analysis confirmed the presence of Zn2+ ions in Zn@MCM-41. The protection using methyl group on the outer/both surfaces of MCM-41 (Me-MCM-41/MeS-MCM-41) disclosed the necessity of interaction between silica surface and metal ion for selective adsorption of Zn2+ ions. The detailed investigation of adsorption mechanism postulates that the selective adsorption of Zn2+ ions by MCM-41 was achieved only in the presence of sodium chloride, which is the major component of artificial seawater. An adsorbed amount of 12 mg g−1 was observed for Zn2+ ions even in presence of Cd2+ ions, while both of the ions possess similar chemical characteristics. [Display omitted] •Calcined MCM-41 (Pristine-MCM-41) was used for the adsorption of metal ions.•The materials were found to be 100% selective for Zn2+ from artificial seawater.•Detailed adsorption mechanism was studied for the selective adsorption of Zn2+.